vector insert functions

I've been trying to use the vector insert functions to insert white
spaces at the front of my string vector, but I can't get it to work.
Will anyone provide some simple exampe(s) of how these functions are or can be used?
Thanks.

>I've been trying to use the vector insert functions to insert white spaces at the front of my string vector
If you are doing a great deal of insertions at the front of the vector then you should be using a deque. vector insertions anywhere except the end tend to be expensive.

>What do you mean by expensive?
To add at the front of a vector, all of the current elements have to be shifted down by one to make room. This memory shift is very inefficient when compared to a deque, where insertion at the front is immediate: